Currently, the obese population is gradually increasing. Obesity is a serious disease that causes diabetes, hyperlipidemia and cardiovascular diseases leading to death. Obesity is a serious health and social issue not only in advanced countries including the USA, but also in Korea. In the USA, costs for treating obesity account for about 6% of the total health-related costs, and in Korea, the obesity treatment market size is approaching one trillion Won (Korean currency). Obesity treatment agents are representative quality-of-life (QOL) improvers together with erectile dysfunction treatment agents and hair loss treatment agents.
Obesity refers to a condition in which adipocytes in the body proliferate and differentiate due to metabolic disorders, and thus fat is excessively accumulated. If energy absorption is higher than energy consumption, the number and volume of adipocytes increase, resulting in an increase in the mass of adipose tissue (Otto et al, Crit Rev Biochem Mol Biol., 40(4):229-242, 2005). Obesity at the cellular level is understood as the increase in number and volume of adipocytes caused by stimulation of the proliferation and differentiation of adipocytes (Hirsch et al, Clin Endocrinol Metab., 5(2):299-311, 1976).
Current methods for treating obesity include drug-independent methods in which an excess of energy is consumed through exercise. In methods of treating obesity with drugs, there are used appetite suppressants that suppress appetite to limit calorie uptake, lipase inhibitors, bulk laxatives, energy stimulating agents, etc. The appetite suppressant sibutramine is a drug that was originally used as an antidepressant, and exhibits the effect of inhibiting the reuptake of serotonin in synapse to thereby provide quick satiety. However, this drug was reported to have various side effects, including cardiovascular action, central action, hepatic disorders and renal disorders. Orlistat acts to discharge fat from the body by inhibiting the function of the digestive enzyme lipase that degrades fat to help the absorption of fat in the body. However, Orlistat is known to have a serious side effect such as fecal incontinence, and the effect thereof cannot be guaranteed in the case of Koreans who live largely on carbohydrates.
Particularly, in the case of women, estrogen levels are lowered after the menopause while abdominal fat is accumulated. In addition, the risk of complications such as type 2 diabetes, cardiovascular diseases or osteoporosis also increases. Estrogen is an important hormone that is secreted from the female ovary and is involved in the development of uterine mucous membranes and mammary glands, the appearance of female secondary sex characters, the control of sexual cycles, and the maintenance of pregnancy. In recent years, it was reported that female hormones are involved in non-reproductive tissue (i.e., bone structure), cardiac blood vessels (lipid metabolism), dementia, colon cancer, teeth, macular degeneration, adipolysis, skin and collagen tissue production, etc., and thus play a very important role in women' health. In the case of hormone replace therapy (HRT) that was a potential menopausal symptom relief therapy for a while, HRT has a high risk of causing breast cancer, heart attack, stroke, cardiovascular diseases, etc., when it is applied over a long period of time. For this reason, the FDA announced to prohibit the long-term administration of female hormone drugs.
Thus, there is an urgent need for a new obesity treatment agent that cause less side effects and has guaranteed effects, and the demand for this obesity treatment agent is continuously increasing.
Accordingly, the present inventors have made extensive efforts to solve the above-described problems occurring in the art. As a result, the present inventors have developed a novel fat accumulation inhibitory peptide which has the function of inhibiting the differentiation of mesenchymal stem cells into adipocytes to thereby inhibit the accumulation of adipose tissue, similar to estrogen, and have found that the developed peptide has the effect of preventing or treating obesity, thereby completing the present invention.